1. Field of the Invention
The present invention relates to an object position detection device and a method thereof, particularly to a position detection device and a method thereof that utilizes an image capturing system to dynamically detect the position of an object.
2. Description of the Related Art
With the development of science and technology, distance detection technologies have been applied to many daily living facilities to promote the safety and convenience of living. For example, due to drivers are more and more concerned about driving safety nowadays, automobile manufacturers have proposed many safety schemes. Among them, collision-forewarning technologies attracts great attentions, including lane departure warning systems, vehicle parking assistance systems, and blind-spot detection systems. Especially, the blind-spot detecting systems contribute most to driving safety and are gradually valued by the market. The abovementioned blind-spot refers to the area a driver cannot watch from the rear-view mirrors. In the blind-spot detection systems, cameras are mounted on two sides of a vehicle to capture the rear-view images of blind-spots, and the driver is alerted when vehicles are approaching. Therefore, the technologies of estimating the distance of the approaching vehicle are needed by the blind-spot detection system. Among them, the distance detection radar is the most popular technology in the market. The distance detection radar adopts an ultrasonic distance detection technology, or an infrared distance detection radar, etc., to detect distance, wherein electromagnetic or ultrasonic energy is directionally emitted to space, and the energy reflected by the object in the space is used to estimate the direction, altitude and speed. Some vehicular radar may even detect the shape of an object. For example, the ground detection radar can accurately detect the profile of the ground surface. However, the vehicular radars usually have a smaller view field and have their blind spots. The range of the blind spots correlates with the number of the mounted vehicular radars. For example, the blind-spot region of a four-eyed backing radar system is better than a two-eyed backing radar system. However, a four-eyed backing radar system is double the price of a two-eyed backing radar system. Besides, the backing radar has a limited detection distance and is hard to detect an object moving in a large area. Another technology to detect a moving object is the vehicle-carried image system, which can overcome the problem of blind spots, whereby the driver can watch the images of the entire blind spots region from the display device. The prior art object recognition technology of vehicle imaging system usually adopts a gradient estimation method and an edge detection method to find the position of an object and then uses a cluster analysis method to define the position of the object. Nevertheless, the abovementioned technology still has some shortcomings to improve. Alternatively, a image comparison method is used to search different image regions. However, the recognition capability is dependent on the adaptability of templates. Besides, the search is time-consuming. Alternatively, indices are used to extract the significant values of various images, and then an artificial intelligence mode is constructed to identify objects. However, it is hard to implement the technology into an existing system.
For a vehicle imaging system, the response thereof should be instant, and the recognition algorithm thereof should be exempted from the influence of environmental illumination so that a certain level of reliability can be achieved. The three technologies mentioned above all consume a lot of resources of a digital signal processor to process images. Further, two different algorithms are usually used to deal with different illumination conditions of day and night. To solve the above-mentioned problems, the present invention proposes an object position detection device and a method thereof. The present invention converts a 2-D (two-dimensional) image data, such as a road image captured by a vehicle imaging system, into 1-D (one-dimensional) distance-axis signal information. The present invention can all-weather accurately detect an approaching object according to a differential value of the 1-D distance-axis signal information at a single time point and the difference of the 1-D signal information of two adjacent time points. The present invention can apply to existing imaging systems with a higher accuracy and a lower cost.